1. Field of the Invention
This invention relates to an antioxidant carotenoid composition substantially free of lutein comprising a lutein ester having beneficial antioxidant properties and high bioavailability. This lutein ester composition may be used in antioxidant compositions or preparations that can be administered to humans to provide protection from the harmful, health-damaging effects of free radicals on various body tissues.
2. Background
Carotenoids are phytonutrients, the nutritional elements that give fruits and vegetables their orange, yellow, and red colors. Green leafy vegetables are also high in carotenoids, but the color is masked by chlorophyll. Although .beta.-carotene may be the best-known and most abundant dietary carotenoid, approximately 500 carotenoids, including lutein, lycopene, cryptoxanthin and zeaxanthin, have been identified. Carotenoids provide health benefits, primarily because of their antioxidant properties. Such benefits include protecting the body from skin, eye, liver, and lung damage, and certain forms of cancer.
Recent scientific studies have provided evidence that antioxidants are capable of protecting healthy cells from free radical damage. Free radicals are unstable chemicals formed in the body during metabolism and from exposure to environmental sources, such as air pollution, cigarette smoke, and dietary fats. When there is an excessive number of free radicals in the body, free radicals can attack healthy cells and can contribute to a number of degenerative diseases, such as cancer.
Free radicals have been linked to numerous diseases and health conditions. Conditions associated with free radicals and affecting multiple organs include: inflammatory-immune injury (idiopathic and membranous glomerulonephritis, vasculitis caused by hepatitis B virus and intravenous drug use, autoimmune diseases); ischemia-reflow states; drug- and toxin-induced reactions; iron overload (idiopathic hemochromatosis, dietary iron overload, thalassemia, and other chronic anemias); nutritional deficiencies (Kwashiorkor, Vitamin E deficiency); alcohol damage; radiation injury; aging (premature aging disorders, age-related immunodeficiency); cancer; and amyloid diseases. Conditions relating to specific organs or tissues and associated with free radicals include: erythrocytes, lead poisoning, protoporphyrin photo-oxidation, malaria, sickle-cell anemia, favism, Fanconi anemia); lung (effects of tobacco smoking, emphysema, hyperoxia, bronchopulmonary dysplasia, oxidant pollutants, acute respiratory distress syndrome, mineral dust pneumoconiosis, bleomycin toxicity, paraquat toxicity); rheumatoic arthritis and other joint abnormalities; heart and cardiovascular (alcohol cardiomyopathy, Keshan diseases (selenium deficiency), atherosclerosis, doxorubicin toxicity); kidney (nephrotic antiglomerular basement membrane disease, aminoglycoside nephrotoxicity, heavy metal nephrotoxicity, renal graft rejection); gastrointestinal tract (endotoxin liver injury, carbon tetrachloride liver injury, diabetogenic action of alloxan, free fatty-acid induced pancreatitis, nonsteroidal anti-inflammatory drug-induced lesions); brain (hyperbaric oxygen, neurotoxins, senile dementia, Parkinson's disease (MPTP), hypertensive cerebrovascular injury, cerebral trauma, allergic encephalomyelitis and other demyelinating diseases, ataxia-telangiectasia syndrome, potentiation of traumatic injury, aluminum overload, abetalipoproteinemia); eye (cataractogenisis, ocular hemorrhage, degenerative retinal damage, premature retinopathy, photic retinopathy); and skin (solar radiation, thermal injury, porphyria, contact dermatitis, photosensitive dyes, Bloom syndrome).
Antioxidants quench free radicals before they have a chance to attack healthy cells. Antioxidants have been shown in the majority of studies to lower the risk for certain cancers, such as lung, stomach, cervix, breast, bladder, and oral cancers. Other health benefits include protection against heart diseases, cataracts, and age-related macular degeneration. While free radicals can cause or complicate many diseases, including cancer, arthritis, cataracts, and heart diseases, antioxidants can help protect the body from these chronic disorders. They also enhance the body's immune system.
One of the most common carotenoid compounds, lutein (also referred to as vegetable lutein or vegetable luteol, xanthophyll, or .beta.,.epsilon.-carotene-3,3'-diol) has the following formula (I): ##STR1##
A carotenoid alcohol, lutein is found naturally in many sources, such as egg yolk, nettles, algae, and the petals of many yellow flowers. Lutein is also one of the major constituents of green vegetables and fruits such as broccoli, green beans, green peas, Brussels sprouts, cabbage, kale, spinach, lettuce, kiwi, and honeydew. Lutein is also present in many plants in the form of mono- or diesters. For example, lutein dipalmitate, also known as helenien or Adaptinol, is present in Helenium autumnale L., Compositae, and other flowers. Lutein can be isolated from these materials using procedures well-known in the art. See, e.g., Karrer et al. (Helv. Chim. Acta 30:531 (1947)).
Lutein in its free or unesterified form is also found in the human bloodstream, presumably as a result of dietary absorption of lutein in food. Because of this and concerns about the suitability of lutein esters for human consumption, prior art methods of increasing plasma lutein concentrations have emphasized dietary supplements containing free lutein. See, U.S. Pat. No. 5,382,714.